defmodule MvWeb.Components.BulkActionsDropdown do
  @moduledoc """
  Single "Aktionen" dropdown bundling the four member bulk actions, flattened to
  one level: open in email program (mailto), copy email addresses, export to CSV,
  export to PDF.

  It keeps the CSRF-protected `<form>` POST export items unchanged (CSV/PDF) and
  adds the mailto and copy items that previously lived as standalone header
  buttons next to a separate export dropdown.

  ## Scope and trigger badge

  The trigger reads `Aktionen` followed by a scope badge: an emphasized
  (`primary`) count `N` when `N` members are selected, and a muted (`neutral`)
  badge otherwise — `gefiltert` when a search term or filter narrows the list,
  `alle` when nothing is selected and no search/filter is active. Only an actual
  selection is emphasized. The badge sits inside the shared `dropdown_menu/1`
  trigger via its `trigger_badge` slot, matching the member-filter dropdown's
  count badge. The `scope`, `selected_count`, `mailto_bcc`, `recipient_count`
  and `mailto_disabled?` are computed by the parent LiveView and passed in.

  ## Recipient handling (mailto / copy)

  The parent already excludes members without an email when building
  `mailto_bcc` and `recipient_count` (defensive filter preserved verbatim from
  the previous behaviour). Export, by contrast, still includes every member in
  scope regardless of email — its payload is unchanged.

  ## Mailto recipient cap

  A mailto URI carries every recipient in its BCC; browsers cannot reliably hand
  a very long mailto over to the mail program. When `mailto_disabled?` is true
  (recipient count at or above `Mv.Constants.max_mailto_bulk_recipients/0`) the
  mailto item is rendered disabled (`aria-disabled`, `tabindex="-1"`, href
  dropped) with an explanatory tooltip. Copy and Export have no such cap.

  ## Event routing

  `dropdown_menu/1` sends `toggle_dropdown`/`close_dropdown` to `@myself`, so the
  component owns its own `:open` state. The copy item carries an *un-targeted*
  `phx-click="copy_emails"`, which therefore reaches the parent LiveView's
  `handle_event/3` (which keeps access to `@members`), plus the
  `CopyToClipboard` hook.
  """
  use MvWeb, :live_component
  use Gettext, backend: MvWeb.Gettext

  # Same focus ring as CoreComponents button/dropdown (WCAG 2.4.7)
  defp dropdown_item_class do
    focus =
      MvWeb.CoreComponents.button_focus_classes()
      |> Kernel.++(["focus-visible:ring-inset"])
      |> Enum.join(" ")

    "flex items-center gap-2 px-2 py-1 rounded cursor-pointer hover:bg-base-200 w-full text-left whitespace-nowrap #{focus}"
  end

  @impl true
  def mount(socket) do
    {:ok, assign(socket, :open, false)}
  end

  @impl true
  def update(assigns, socket) do
    socket =
      socket
      |> assign(:id, assigns.id)
      |> assign(:export_payload_json, assigns[:export_payload_json] || "")
      |> assign(:selected_count, assigns[:selected_count] || 0)
      |> assign(:scope, assigns[:scope] || :all)
      |> assign(:mailto_bcc, assigns[:mailto_bcc] || "")
      |> assign(:recipient_count, assigns[:recipient_count] || 0)
      |> assign(:mailto_disabled?, assigns[:mailto_disabled?] || false)

    # The parent never sets :open (the component owns it via toggle/close).
    # Honouring an explicit :open assign keeps the component renderable in
    # isolation (render_component/2) for structural tests.
    socket =
      case Map.fetch(assigns, :open) do
        {:ok, open} -> assign(socket, :open, open)
        :error -> socket
      end

    {:ok, socket}
  end

  @impl true
  def render(assigns) do
    assigns =
      assigns
      |> assign(:scope_label, scope_label(assigns))
      |> assign(:scope_variant, scope_variant(assigns))

    ~H"""
    <div id={@id} data-testid="bulk-actions-dropdown" class="flex-auto flex-wrap">
      <.dropdown_menu
        id={"#{@id}-menu"}
        button_label={gettext("Actions")}
        icon="hero-bolt"
        open={@open}
        phx_target={@myself}
        menu_width="w-70"
        menu_align="left"
        button_class="btn-secondary gap-2"
        testid="bulk-actions-dropdown"
        button_testid="bulk-actions-button"
        menu_testid="bulk-actions-menu"
      >
        <:trigger_badge>
          <.badge variant={@scope_variant} size="sm" data-testid="bulk-actions-scope-badge">
            {@scope_label}
          </.badge>
        </:trigger_badge>
        <li role="none">
          <.mailto_item mailto_bcc={@mailto_bcc} disabled={@mailto_disabled?} />
        </li>
        <li role="none">
          <button
            type="button"
            role="menuitem"
            id="bulk-actions-copy"
            phx-hook="CopyToClipboard"
            phx-click="copy_emails"
            class={dropdown_item_class()}
            aria-label={gettext("Copy email addresses")}
            data-testid="bulk-actions-copy"
          >
            <.icon name="hero-clipboard-document" class="h-4 w-4" />
            <span>{gettext("Copy email addresses")}</span>
          </button>
        </li>
        <li role="none">
          <form method="post" action={~p"/members/export.csv"} target="_blank" class="w-full">
            <input type="hidden" name="_csrf_token" value={Plug.CSRFProtection.get_csrf_token()} />
            <input type="hidden" name="payload" value={@export_payload_json} />
            <button
              type="submit"
              role="menuitem"
              class={dropdown_item_class()}
              aria-label={gettext("Export members to CSV")}
              data-testid="export-csv-link"
            >
              <.icon name="hero-document-arrow-down" class="h-4 w-4" />
              <span>{gettext("Export to CSV")}</span>
            </button>
          </form>
        </li>
        <li role="none">
          <form method="post" action={~p"/members/export.pdf"} target="_blank" class="w-full">
            <input type="hidden" name="_csrf_token" value={Plug.CSRFProtection.get_csrf_token()} />
            <input type="hidden" name="payload" value={@export_payload_json} />
            <button
              type="submit"
              role="menuitem"
              class={dropdown_item_class()}
              aria-label={gettext("Export members to PDF")}
              data-testid="export-pdf-link"
            >
              <.icon name="hero-document-text" class="h-4 w-4" />
              <span>{gettext("Export to PDF")}</span>
            </button>
          </form>
        </li>
      </.dropdown_menu>
    </div>
    """
  end

  # The mailto item is an anchor menu item. When over the recipient cap it is
  # rendered disabled following the same a11y pattern as a disabled CoreComponents
  # link button (href dropped, tabindex=-1, aria-disabled=true) and exposes the
  # explanatory tooltip via title.
  attr :mailto_bcc, :string, required: true
  attr :disabled, :boolean, required: true

  defp mailto_item(%{disabled: true} = assigns) do
    assigns = assign(assigns, :item_class, dropdown_item_class())

    ~H"""
    <a
      role="menuitem"
      tabindex="-1"
      aria-disabled="true"
      title={over_threshold_tooltip()}
      class={[@item_class, "opacity-50 pointer-events-none"]}
      aria-label={gettext("Open in email program")}
      data-testid="bulk-actions-mailto"
    >
      <.icon name="hero-envelope" class="h-4 w-4" />
      <span>{gettext("Open in email program")}</span>
    </a>
    """
  end

  defp mailto_item(%{disabled: false} = assigns) do
    assigns = assign(assigns, :item_class, dropdown_item_class())

    ~H"""
    <a
      role="menuitem"
      tabindex="0"
      href={"mailto:?bcc=" <> @mailto_bcc}
      class={@item_class}
      aria-label={gettext("Open in email program")}
      data-testid="bulk-actions-mailto"
    >
      <.icon name="hero-envelope" class="h-4 w-4" />
      <span>{gettext("Open in email program")}</span>
    </a>
    """
  end

  defp over_threshold_tooltip do
    gettext("Too many recipients for this function. Copy the addresses or export the list.")
  end

  # The trigger scope is shown as a badge after the "Aktionen" label. Only an
  # actual selection is emphasized (primary); both the "filtered" and "all"
  # scopes are muted (neutral), since neither means members are selected.
  defp scope_label(assigns) do
    case assigns.scope do
      :selection -> to_string(assigns.selected_count)
      :filtered -> gettext("filtered")
      _ -> gettext("all")
    end
  end

  defp scope_variant(assigns) do
    case assigns.scope do
      :selection -> "primary"
      _ -> "neutral"
    end
  end

  @impl true
  def handle_event("toggle_dropdown", _params, socket) do
    {:noreply, assign(socket, :open, !socket.assigns.open)}
  end

  def handle_event("close_dropdown", _params, socket) do
    {:noreply, assign(socket, :open, false)}
  end
end